Vitamin D: Are you getting enough?

The odds are that you aren’t getting enough vitamin D from your diet or from the sun and that you need to be taking vitamin D supplements, as I’ll explain below. I recently had a routine physical examination and blood work done and while most everything turned out fine, my vitamin D levels were found to be low. And since there are no symptoms of vitamin D deficiency, I wouldn’t have otherwise known about it before I developed osteoporosis (which would be a bit late in the game I think). Moreover, adequate vitamin D levels are now being recognized as important not only in preventing osteoporosis, but also in preventing several types of cancer, cardiovascular disease, falls, chronic pain syndromes and a variety of autoimmune diseases (with the list growing on a nearly daily basis). Evidence is mounting that vitamin D is critical to our health and that all too many of us are deficient.

There are two ways that humans get vitamin D aside from taking supplements; namely, from the diet and by its production in our skin after exposure to sunlight. It turns out, however, that few foods contain much vitamin D, which is why some are “fortified” with it, meaning that they have extra vitamin D added during production (e.g., milk, and some breakfast cereals, orange juice, yogurt and margarine – with the list increasing as vitamin D deficiency is more widely recognized). So it would be fairly easy not to get much dietary vitamin D, unless you made a conscious effort to eat lots of fortified foods.

What about sun exposure? Turns out again, that for many Americans sun exposure also is inadequate, especially in winter. The reasons are both conscious sun avoidance (or wearing sunblock) in an effort to prevent skin cancer and living at higher latitudes where the sun’s rays don’t have as much effect, particularly during the winter months. In this regard, higher latitude means living above 30°, which is nearly all of the U.S. (for example, this latitude runs through Jacksonville, FL, New Orleans, LA, and Austin, TX – in fact, there’s very little of the continental U.S. below 30°, and it’s mostly in Florida). In addition, our skin’s ability to produce vitamin D declines with increasing age.

For me, being 57 years old, living in Seattle and eating a normal diet without a lot of fortified foods, means that having vitamin D deficiency (when tested in the spring) is basically, but unfortunately, to be expected! In one study of 290 patients hospitalized for various reasons, vitamin D deficiency was found in 164 (57 percent), of whom 65 (22 percent) were considered severely deficient. In a subgroup of 77 patients who were less than age 65 and who had no known risk factors, the prevalence of vitamin D deficiency was still 42 percent. In another study of healthy young adults (ages 18-29) in Boston, 36 percent were vitamin D deficient at the end of winter (this declined to only 4 percent by the end of summer).

In summary:
• Vitamin D is very important to your health.
• Vitamin D is inadequate in most U.S. diets.
• Vitamin D production in the skin is inadequate during the winter in most parts of the U.S.
• Vitamin D production in the skin and vitamin D stores decline with age.
• Vitamin D deficiency is common and basically has no symptoms until it’s too late.

The bottom line is that you should be taking vitamin D supplements. The Recommended Dietary Allowance (RDA) for vitamin D for people age 14-50 is 200 IU/day, for those 51-70, 400 IU/day and for those over 71, 600 IU/day. But it is widely believed that these numbers are way too low and that the average adult needs at least 800-1000 IU/day. Some experts recommend 1200-1500 IU/day. Please note that if you are monitoring the foods you eat and the supplements you take, pay attention only to the number of IU’s (International Units) and not to the percent of the RDA provided. That’s because, as noted above, the RDA’s are too low and something labeled as having 100 percent of the vitamin D RDA might only have 2-400 IU.

Depending on your age, your diet, your sun exposure and where you live, you may also want to consider having your doctor check the vitamin D levels in your blood. The reason is that if you, like me, turn out to be deficient, you may need to take much larger doses of vitamin D for 1-2 months to replenish your stores, after which you can then take the recommended 800-1000 IU/day. I’m now taking the recommended replenishing dose of 50,000 IU once a week for 6-8 weeks (it’s a prescription product and even though it sounds like a large amount, it’s only a small capsule). After taking this dose I’ll have another blood test to make sure my levels are back to normal, and then I’ll be taking at least 1000 IU/day after that.

What’s your experience with vitamin D been? Please leave a comment below so that others can learn from your experience. We look forward to hearing from you.

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ABOUT THE AUTHOR

Ed Zimney, MD

Ed is a physician with more than 30 years of experience. He’s held positions in drug advertising review, drug safety surveillance, medical information and marketing with several bio/pharmaceutical companies.

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